As one of the processes performed in photolithography of forming a coating film pattern on a semiconductor wafer (hereinafter, referred to as a wafer) as a substrate, there is a process of forming a coating film on a front surface of the wafer. In a coating module that performs such a process, for example, a coating liquid is supplied onto a central portion of the wafer which is rotating while being mounted on a spin chuck so that a coating film is formed on the wafer. When the coating film is formed on the surface of the wafer in this manner, there may be a case where an end portion of the coating film is removed to remove an unnecessary film in a peripheral portion of the coating in a ring shape or a rear surface of the wafer is cleaned by the coating module. The removal of the end portion of the coating film is performed by locally discharging a solvent of the coating film from a nozzle to the peripheral portion of the wafer which is rotating by the spin chuck. The cleaning of the rear surface is performed by discharging a cleaning liquid from a cleaning nozzle toward the rear surface of the wafer which is rotating by the spin chuck.
In such a coating module, when a new coating liquid or cleaning liquid is used, an adjustment operation is carried out in advance on parameters that may affect the removal of the end portion of the coating film or the cleaning of the rear surface prior to actually processing a semiconductor wafer as a product. Conventionally, after a predetermined process is performed on a wafer for parameter adjustment in the coating module, the respective wafer is transferred to an inspection apparatus such as, e.g., a microscope or the like. In this inspection apparatus, the front surface or the rear surface of the wafer is observed to recognize a cutting state or a cleaning state of the end portion of the coating film, and change values of the parameters based on the recognized state. Then, a predetermined process is again performed in the coating module using the changed parameters, and thereafter, an inspection is conducted in the inspection apparatus to adjust the parameters. That is to say, the adjustment was made in a trial and error manner. Therefore, it takes a lot of time and labor and an experienced operator is needed to adjust the parameters, which is a complicated work.
For example, a technique has been used to set parameters within an appropriate range by approximating a film thickness distribution to a linear function and a quadratic function which indicate a relationship between a position and a film thickness of the substrate, and changing the parameters for adjusting the film thickness of the coating film based on these functions. However, this technique does not take into consideration parameters which may affect the cutting state of the end portion of the coating film or the cleaning state of the rear surface of the wafer.
Further, there is another technique which images an end portion surface of the substrate to obtain a shape data of the end portion surface, recognizes an amount of warping of the substrate, and determines a supply position of a solvent based on the warp amount, when removing an unnecessary film by supplying the solvent to a peripheral portion of a coating film after forming the coating film. However, this technique does not adjust parameters by recognizing the cutting state of the end portion of the coating film or the cleaning state of the rear surface of the substrate.